Early in the days of my work on the measurement of experience, I saw Verdi’s opera “La Traviata.” Known for its gorgeous music, it is also a moving story of the love between a young aristocrat and Violetta, a woman of the demimonde.

Most of us view the world as more benign than it really is, our own attributes as more favorable than they truly are, and the goals we adopt as more achievable than they are likely to be. We also tend to exaggerate our ability to forecast the future, which fosters overconfidence.

Take a look at the photos of two pairs of eyes, and take note: Your heartbeat accelerated when you looked at the left-hand figure. In fact, it accelerated even before you could label what is so eerie about the picture.

In 1738, the Swiss scientist Daniel Bernoulli argued that a gift of 10 ducats has the same utility to someone who already has 100 ducats as a gift of 20 ducats to someone whose current wealth is 200 ducats.